util: Add the scons configuration cache to .gitignore for util/tlm.

Change-Id: Ife31e1bbf862d10bbe8e2c0fa36c8c168cfafa84
Reviewed-on: https://gem5-review.googlesource.com/c/14656
Reviewed-by: Matthias Jung <jungma@eit.uni-kl.de>
Maintainer: Gabe Black <gabeblack@google.com>

misc: minor fix for the gem5-SystemC/TLM coupling.

This patch has a minor fix for the coupling between gem5 and SystemC-TLM.

It also fixes some typos in the related documentation.

Change-Id: I894568729b8ebdacc5b81c9f46e8f9d137da210f
Reviewed-on: https://gem5-review.googlesource.com/2480
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>